Field
The present disclosure relates generally to systems for creating a durable water-resistant seal between adjacent panels subject to temperature expansion and contraction which further provides some protection for exposed surfaces against extreme heat. More particularly, the present disclosure is directed to providing an expansion joint seal system which includes a temperature activated fire retarding material to protect uncoated edges of substrates.
Description of the Related Art
Construction panels come in many different sizes and shapes and may be used for various purposes, including roadways, sideways, and pre-cast structures. Where the construction panels are concrete, it is necessary to form a lateral gap or joint between adjacent panels to allow for independent movement, such in response to ambient temperature variations within standard operating ranges. In light of temperature variations beyond the range, such as incident to a fuel fire or a vehicle fire adjacent the concrete panels, such as roadways or tunnel walls or ceilings, it is further necessary to provide protection to the concrete panels against high temperatures.
Various seal systems and configurations have been used to provide water-retardant seals which also provide fire protection. One technique is to provide a water-retardant seal between construction panels and to overlay the exposed surface of the construction panels with a fire-resistant material, while leaving the water-retardant seal directly exposed to the high temperature. In such systems, the seal system is intended to prevent water and other contaminants from entering the gap or joint between the construction panels during exposure to weather conditions. As the gap or seal is intended to permit expansion of the panels into the gap or seal, the presence of non-flexible contaminants, such as those intended to prevent fire damage, could prevent such expansion and contribute to the increase of stresses and strains within the panels, the seal was permitted to be exposed, while the working surface of the adjacent construction panel was coated with a fire-retardant. Another technique is to provide a compressible foam infused with a fire retardant, which includes an elastomer at its exposed surface and an intumescent at the opposite side, to provide a degree of waterproofing from the exposed surface and a degree of fire-retardant from opposite side or in cases where the elastomer and fire-retardant infused foam were consumed, in whole or in large part, by fire.
These systems, however, do not provide substantive protection of surface of the construction panels perpendicular to the exposed surface against fire. These concrete ends are not protected from the heat, which can cause spalling of the concrete and therefore require replacement of the concrete. Spalling is well-known to be detrimental to the concrete structure, potentially precluding continued use or at requiring substantial and expensive remediation to return to service. While this may be addressed, in part, by overlapping the surface coating and the seal, this has a negative impact on the flexibility of the joint seal.
Alternative systems provide for a backer bar having a combustible closed-cell foam jacket surrounding an intumescent or an intumescent simply having a combustible closed-cell foam cap, wherein a sealant is then applied atop the backer bar. Unfortunately, these systems have little elasticity in light of the composition of intumescent.
Finally, other systems are known wherein the intumescent is positioned as far distant the exposed surface as possible, at the bottom of a spline connected to an expansion joint cover.
It would be an improvement to the art to provide an expansion joint seal which would provide a long-life water-resistant seal through the ambient temperature range which would also provide a degree of intumescent protection of the exposed ends of construction panels in the event of temperature immediately above the ambient temperature range.